The increased processing power that becomes available with each new generation of personal computers provides users with greater opportunities to accomplish a variety of different tasks. A user is no longer confined to performing a single task at any given time on a personal computer. Rather, multitasking has become a common manner of operating the computer. Such multitasking may occur within a single application program, e.g., a user might have several documents open within a word processing or graphics program. Likewise, it can occur across multiple applications. For instance, the user could open a web browser to access one or more web sites on the Internet, while at the same time running an electronic mail program to read messages and a word processing program to paste the content of the messages or web sites into one or more documents.
In graphical user interfaces that employ windows to present data, each task that is being performed by the user may have one or more windows associated with it. For example, each document that is open in a word processing program will have its contents displayed in a separate window. In addition, various functions performed by the program, such as spell checking, print spooling and the like may each have one or more secondary windows associated with them, to provide status information and/or user input. Similarly, every other application program that is running on the computer presents one or more windows to the user. For instance, if a browser is employed to access a number of different types of web sites, e.g., an http site, an ftp site and a news site, the contents of each site might be presented in a different respective window.
It can be appreciated that, as multiple tasks are performed on the computer, the number of windows that are simultaneously displayed can become significant. For the inexperienced user, multiple open windows can be a source of frustration or confusion. More particularly, the windows are presented in a layered manner. Every window has a relative depth associated with it, wherein the most recently accessed, or active, window appears in the foreground of the display, and every other window is located “behind” the active window, in inverse relation to the order in which they were accessed. As a result, a window of interest may become completely overlaid by other, later-accessed windows, thereby blocking it from view. The user may not know how to navigate to the desired window without closing, minimizing, or moving all of the windows that overlie it, which may not be consistent with the operation intended by the user. Even for the more experienced user, a large number of open windows may present a cluttered interface which detracts from the ability to easily access desired information in a particular window.
One approach to solving this problem is described in co-pending, commonly assigned U.S. application Ser. No. 09/447,419, filed Jan. 4, 2000. In this approach, a single-window viewing mode can be selected, in which a single window, or at most a few windows associated with the currently active task, is displayed to the user. All other windows relating to non-active tasks are automatically minimized, to thereby reduce the amount of information presented to the user at any one time.
The present invention is directed to an alternative approach to facilitate navigation among multiple windows of information. More particularly, some users may prefer to keep the windows open for all ongoing tasks, rather than reduce most of them to a minimized state. For instance, it may be desirable to keep multiple windows open to enable their content to be easily copied from one to another. As the number of open windows increases, however, the user's ability to locate the one containing the desired content becomes more difficult.
While the case of overlapping windows readily illustrates the potential for user difficulties, that is not the only situation in which overlapping objects can be a source of inconvenience to the user. For instance, multiple icons in a folder can lie on top of one another, thereby inhibiting the ability of the user to locate one of interest. More generally, almost any type of object that is displayed in a graphical user interface can appear in front of another object, and thereby interfere with the user experience.